Since the time of Animal Care and Use Committee approval of this protocol in December 2015, we have been developing the necessary technical skills in rodent echocardiography and cardiac catheterization. Part 1 of the study, determining the reproducibility of the SU-5416/hypoxia/normoxia model by our group, as well as the development of the necessary catheterization and echocardiography procedures, commenced in August 2016. The study is currently ongoing. Our plans are to continue on to Part 2, determining the effects of spironolactone versus eplerenone in this model by early 2017.